The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
A typical vehicle powertrain includes an engine and a transmission. In certain powertrains, the engine is selectively turned on and off. That is, as the vehicle comes to a stop, the engine is automatically stopped under a predetermined stop condition, and then, under a predetermined restart condition, the engine is restarted. These powertrains may further include a hydraulic control system with an accumulator that is arranged to discharge a fluid to a torque transmitting device, such as, for example, a clutch when the engine is restarted, to accumulate the fluid when the engine is on, and to retain the fluid when the engine is turned off.
Some accumulators discharge the fluid with a piston loaded by a compressed gas and accumulate the fluid by releasing the gas. Such accumulators, however, have to be capable of selectively sealing in pressurized gas. Accordingly, there is room in the art for an accumulator assembly that does not require the complexity associated with sealing pressurized gas within the assembly.